The present disclosure relates to a lateral bipolar junction transistor (BJT) structure, and particularly to a germanium lateral bipolar junction transistor and methods of manufacturing the same.
Germanium has a narrower band gap than silicon, and provides a great potential for providing a fast bipolar junction transistor that operates at low voltages. A silicon BJT typically operates at about 1 V while a germanium BJT typically operates at about 0.6 V. However, manufacture of a germanium-based device has been a challenge because germanium oxide is soluble in water. Thus, the advantageous properties of germanium derived from the narrower band gap has been only partly utilized through use of a silicon-germanium alloy, which has a band gap that is narrower than the band gap of silicon, and is wider than the band gap of germanium.